The present invention is directed to a trailer having a fixed lower deck and an upper deck tiltable down for loading so that it can readily accommodate vehicles or other cargo on both levels.
Trailers pulled by a hauling vehicle are ubiquitous on the nation""s high-ways. These vary in size and configuration from the giants in excess of 50 feet in length used for overland cargo hauling to very light duty types used for hauling small recreational boats. They include low boy configurations for heavy equipment hauling, and flat bed types with no significant superstructure. Some have enclosed boxes while others are of open frame construction, such as auto transports. Most have a single level deck but auto transports and some livestock carriers normally have two levels to increase cargo capacity.
Recreational vehicles are now popular with the American public. These vary from small models having the bare essentials for comfortable camping to large luxury models having deluxe living accommodations. Many of these xe2x80x9cRVsxe2x80x9d, as they are generally called, will also tow a smaller car or a boat for use at stopping points. A small car is far more convenient for local driving than the bus-sized RVs. Many owners would carry both a boat and small car if there was some way to do this but that has not been convenient since trailers that can accommodate both have not been readily available. Woodburn, in U.S. Pat. No. 4,932,830, shows one such double deck trailer. The upper deck is a boat cradle that slides up and down four corner posts and is elevated or lowered by a winch operated cable system. After the boat is loaded and raised an automobile can be driven on the platform below it. However, this arrangement is awkward since no provision is made for a boat trailer. The user is left to his own imagination how the boat can be loaded and unloaded and how it can be subsequently transported from trailer to the water and back.
Swift, in U.S. Pat. No. 3,718,227, shows a similar transport in which the boat trailer actually becomes the upper deck. The trailer and boat are backed onto a flat bed trailer. A pair of toggling arms and cross bar attached to a winch first lifts the rear of the trailer into position. Sequentially a second pair of arms located mid-trailer raises the front. A car may then be driven onto the deck underneath. The boat trailer requires some specific adaptations to be compatible with the system.
In U.S. Pat. No. 6,027,290, Andre shows a two level platform that may be installed on a truck bed, rail car, etc. An upper deck rides in six upright slotted posts and is raised or lowered parallel to a lower deck to accommodate one-above-the other Loads. An elevating system is operated by a hydraulic cylinder and cable arrangement. While these systems are fine for the environments they have been designed for, they lack convenience, simplicity, and safety required by the recreational user.
The present invention is a dual level trailer that is simple in construction and operation. The trailer is eminently suitable for the recreational or other user who wishes to carry more than one item that would conveniently fit on a relatively small flat bed or other type trailer. The construction is based on a conventional flat bed trailer of an appropriate size. This may have a single wheel pair, dual pair, or multiple axles depending on the anticipated load, and will have a conventional hitch at the forward end. The trailer will provide a lower deck for whatever load will be carried.
The trailer deck will normally have a conventional generally rectangular configuration or outline, although this is not absolutely essential. Upright posts to support the upper deck are mounted at each corner. The posts at the forward end of the trailer are fixed in position and appropriately braced. The two posts at the rearward end are pivotally attached at their lower ends so as to have at least some forward and rearward freedom of movement. The upper deck is pivotally attached to the upper ends of the forward posts so that the rearward end can be tilted or sloped down to the level of the lower deck in order to receive a load and then can be raised back to travelling position. There are a pair of sleeves, one mounted at each of the rear corners of the upper deck, that will slide up and down outside the two rear posts when the upper deck is raised or lowered. These must have some limited rotational freedom of movement relative to the upper deck in order to prevent binding during movement. An elevating means serves to raise or lower the upper deck.
The upper deck will have a frame with both longitudinal and lateral structural support members. A preferred construction will provide a tubular transverse means to support the rearward portion of the deck. This may be a single tube or a pair of spaced apart but axially aligned tubes. The sleeves sliding on the uprights will be welded to the ends of the tubular elements. The tubular support means will pass through any longitudinal support members but must have limited rotational freedom of movement relative to them.
A number of possible elevating devices may be used; e.g., hydraulic cylinders, or a cable and winch system for raising or lowering the upper deck. A preferred system is one similar to that shown in the aforenoted Andre patent. A long hydraulic cylinder is mounted at the forward end of the upper deck, preferably located on the underside. A pair of side-by-side cables are attached to the piston rod and extend rearward to a pair of side-by-side pulleys generally centrally located adjacent the rear edge of the upper deck. The pulleys direct the cables laterally left and right to the sleeves. There a second set of pulleys mounted in the sleeves again changes cable direction toward the upper ends of the rear upright posts. The cables are anchored in position at that point. As the piston of the hydraulic cylinder is extended the rear edge of the upper deck is lowered to or about to the point of contact with the lower deck. The opposite motion occurs when the piston is withdrawn back into its cylinder.
With the upper deck in lowered position a boat trailer, all terrain vehicle, or any similar load may be driven or winched into place. Suitable straps or other conventional means will be used for safe load retention while travelling. When the upper deck is raised with its load in place it is preferably latched in place for safe travel by the use of pins placed beneath it in the rear posts or by other suitable retention mechanisms.
It is an object of the present invention to provide a double deck trailer that is of simple construction, easy to load and unload, and with a high degree of safety for its load and operating personnel.
It is another object to provide a double deck trailer in which one end of the upper deck may be tilted down for loading and unloading.
It is a further object to provide such a trailer that has few moving parts so that wear during operation is minimized.
These and many other objects will become readily apparent to those skilled in the art upon reading the following detailed description taken in conjunction with the drawings.